This invention relates to laser recording and projection system and, more particularly, to an arrangement for providing excitation energy for the laser within such a system.
Lasers require radiant energy input in order to excite the ions of the active lasing material into a higher energy level. Various proposals have been made in the past for effecting such excitation. Some of these proposals have even suggested utilizing solar energy. One of the most widely utilized techniques for exciting a laser is to have a linear light source parallel to the rod of lasing material, both enclosed in an elliptical housing and each disposed at a respective focal point of the ellipse. A typical linear light source utilizes a tungsten halogen lamp. A disadvantage of such an arrangement is that it requires cooling of the laser and the light source. However, the physical configuration of the enclosure is inconsistent with good cooling. Accordingly, it is an object of the present invention to provide an improved arrangement for providing excitation energy for a laser with a minimum requirement for cooling the laser.
One use of a laser is in a combined laser recording and color projection system wherein data is recorded by laser action on a recording medium and a projection system projects the data, by backlighting the recording medium, onto a display screen. In such a system, only a portion of the energy spectrum of the projection system is utilized. Accordingly, it would be desirable to be able to utilize the previously wasted projection lamp energy for exciting the laser.